The current FHIR resources for Task and for Procedure seem to completely overlap. Clarifying guidance is needed to direct usage consistently.

Task - "A task resource describes an activity that can be performed and tracks the state of completion of that activity. It is a representation that an activity should be or has been initiated, and eventually, represents the successful or unsuccessful completion of that activity." (http://build.fhir.org/task.html)

Procedure - "This resource is used to record the details of current and historical procedures performed on a patient. A procedure is an activity that is performed with or on a patient as part of the provision of care. Examples include surgical procedures, diagnostic procedures, endoscopic procedures, biopsies, counseling, physiotherapy, exercise, etc. Procedures may be performed by a healthcare professional, a friend or relative or in some cases by the patient themselves." (http://build.fhir.org/procedure.html)

Thus - a Task might be a Procedure, and a Procedure might be a Task. In which scenarios should each be used? If they are completely interchangeable, the resulting confusion will be problematic. Note that Task includes the ability to request and to perform a task. Procedure requires use of ServiceRequest to propose, plan or order it.

Please clarify.